The original Dragon Ball had loads of epic music. The opening and ending are great, but what really takes the cake is "Moeru Heart De ~ Red Ribbon Gun Wo Yattsukero ". The Red Ribbon Army saga might've dragged out at times, but playing this just before the climax to recap everything really made it larger than life.
If we are going to talk about the opening themes, then we must talk about the opening theme of Dragon Ball, Makafushigi Adobencha (translated in English as Mystical Adventure)! Just... listen and enjoy! Or else!
Mezase Tenkaichi, which played during quite a few epic scenes from the various tournaments throughout the series.
Hironobu Kageyama being one who has his own section in the Awesome Music department made a large number of hits for Dragon Ball, starting with "Spirit vs Spirit". For those not in the know this was the theme that reflected Gohan's emotions when he fought Cell.
Regardless of what you think about the English dub of Dragon Ball Z, Faulconer Productions wrote some pretty epic music for it. Highlights include: Vegeta - Super Saiyan, which usually meant Vegeta was doing something totally awesome, Ginyu Transformation, generally played when a major villain died or during other particularly epic moments, and SSJ3 Power-Up.
Piccolo's theme sets the tone for pretty much every moment that Piccolo has, whether it be getting ready to go to a fight he's not sure he'll survive, to watching over the world as everything goes to hell. It's serious and determined, yet calm and serene. A perfect match for his character, and one of the most awesome songs in the show.
Yushi No Gaisen translated as "The Braveheart's Triumphant Return", one of Goku's themes. Used for his "I AM" speech, and this time it was accurately dubbed as well
On the topic of songs with "Braveheart" in them, we also have Kyousha He Idomu Yuushi, translated as "The Braveheart Challenges The Strong", used in pretty much any scene where the good guys start kicking butt.
This fan remix, which has the first four versions of "Dragon Soul" edited together to form a quartet. It. Is. AWESOME. Funimation must have liked this idea, because guess what the version they did for their volume 7 DVD set was?
The original Dan Dan Kokoro Hikareteku by Field of View fits the first season's "quest for the dragon balls" premise, but as soon as they start fighting Baby (which, mind you, is when the show actually starts getting good), the rap/rock opening really sums up the epicness of the whole thing.
You could pretty much count the vast majority of Yamamoto's music for the games (as well as Kai) over the years. The overkill on Suspiciously Similar Songs which inevitably got him canned from the franchise may or may not affect this, though.
Problems aside, Dragonball Evolution did have one thing going for it: the director wanted a Japanese singer to do the movie's theme song since it was based off a Japanese property, so who does he get? Ayumi Hamasaki. Whoa. Admittedly, Brian Tyler's score for the whole thing does make it seem a little more epic.